1.DDD与Spring Data
DDD: domain-driven design(领域驱动设计)是复杂需求下软件开发的实现方式。有时间我将专门来讲解一下DDD。
Spring Data在很多地方都是按照DDD原则进行的设计(如Repository), 这里Spring Data主要是实现了DDD的aggregate和domain event:
下面我们演示一个当Person这个aggregate root 保存成功后，通过Person的gender属性对统计实体GenderStat更新男女性别的统计数量。
2.演示
2.1 Person Aggregate Root
Person作为Aggregate Root具备发布domain event的能力，在Spring Data 下可以有两种实现方式:
如：
@Entity
@Data
@AllArgsConstructor
@NoArgsConstructor
@ToString(exclude = "domainEvents")
public class Person {
@Id
@GeneratedValue
private Long id;
private String name;
private Integer gender;//1:male;2:female
@DomainEvents
Collection<Object> domainEvents() {
List<Object> events= new ArrayList<Object>();
events.add(new PersonSavedEvent(this.id,this.gender));
return events;
}
@AfterDomainEventPublication
void callbackMethod() {
//
}
}
或
@Entity
@Data
@AllArgsConstructor
@NoArgsConstructor
@ToString(exclude = "domainEvents")
public class Person extends AbstractAggregateRoot{
@Id
@GeneratedValue
private Long id;
private String name;
private Integer gender;//1:male;2:female
public Person afterPersonSavedCompleted(){
registerEvent(new PersonSavedEvent(this.id,this.gender));
return this;
}
}
2.2 监听事件处理
@Component
public class GenderStatProcessor {
@Autowired
GenderRepository genderRepository;
@Async
@TransactionalEventListener
public void handleAfterPersonSavedComplete(PersonSavedEvent event){
GenderStat genderStat = genderRepository.findOne(1l);
if(event.getGender()==1){
genderStat.setMaleCount(genderStat.getMaleCount()+1);
}else {
genderStat.setFemaleCount(genderStat.getFemaleCount()+1);
}
genderRepository.save(genderStat);
}
}
3 源码地址：https://github.com/wiselyman/spring-data-domain-event
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。
